A cover gasket 51 for a hard disc device (HDD) is structured, as shown in FIG. 5, such that a packing 53 made of a rubber-like elastic material is firmly fixed to one surface of a cover plate 52 made of a metal with a predetermined plane arrangement in accordance with an adhesive bonding means, a baking means or the like. In particular, the cover gasket 51 for a compact hard disc device is structured such that a cross sectional shape of the packing 53 is formed in an asymmetrical shape in view of a width direction (a lateral direction on the drawing), as shown in FIG. 6, and a lip portion 54 is compressed by the opposing base plate 55 at a time of assembling a product as shown in FIG. 7 so as to be bent to an inner peripheral side (a left side on the drawing), thereby securing a dustproof property and an airtightness.
However, in accordance with the conventional cover gasket 51, since a round shape and a compression rate of the packing 53 are set comparatively larger in a position close to a screw fixing portion 56 fixing the cover plate 52 to the opposing base plate 55 by screw than those in the other positions, there is a disadvantage that the packing 53 tends to be peeled off from the cover plate 52 due to an influence of a bending moment (an arrow M) or the like caused by a compression.
Further, there is a disadvantage that the packing 53 tends to be peeled off from the cover plate 52 in a bent portion in which the packing 53 is bent or curved or crossed in a plane shape thereof in the same manner, in addition to the screw fixing portion 56.
The present invention is made by taking the points mentioned above into consideration, and an object of the present invention is to provide a gasket in which a packing is adhered to one surface of a plate with a predetermined plane arrangement, wherein the gasket has a structure in which the packing is hard to be peeled off from the plate to which the packing is firmly fixed.